Method of dyeing nitrogenous fibers with premetalized azo dyes and compositions therefor



United States Patent 9 METHOD OF DYEING NITROGENOUS FIBERS WITH PREMETALIZED AZO DYES AND COM- POSITIONS TIEREFOR Chester A. Amick, Bound Brook, N.J., assignor to American Cyanamid Company, New York, N.Y., a corporation of Maine No Drawing. Filed Dec. 19, 1956, Ser. No. 629,225

11 Claims. (Cl. 8-43) This invention relates to a new method of dyeing metalized azo dyes containing an orthoamino group and to new dyeing compositions.

Metalized azo dyes have achieved widespread use, particularly in the dyeing of basic nitrogenous fibers, such as wool. A common process is to form the metal complex of the dye and then dye with the premetalized dye.

A completely metalized dye will normally have one atom of metalizing metal for each metalizable azo group. Any demetalization during dyeing results in a change of shade and frequently produces a duller shade. The problem is particularly acute with metalized dyes having an amino group ortho to the azo group.

According to the present invention, premetalized dyes having an amino group ortho to the azo group are dyed in the customary acid bath in the presence of a dyeing assistant which is a diester of oxymethylene glycols having the general formula:

where R is hydrogen, alkyl or an aryl radical and m and n are integers, m being 1, 2 or 3 and n being 0, 1, 2, 3 or 4.

The present invention is not limited to any theory of the exact mechanism by which the dyeing assistants improve the dyeing. It seems probable that at least one factor may be an effect on the decomposition of the dyestuif during the dyeing and that the dyeing assist-ants may prevent or reduce demetalization. In any event, better dyeings are obtained which equal or approximate the shade of the premetalized dye. The invention is not limited to the tentative explanation presented above as it may be that other factors also are involved. Inasmuch as the shade is the same as the original premetalized dye, it seems probable that little or no demetalization takes place, and this may be the only reason for the brighter shades obtained by the present invention.

The degree of improvement obtained by means of the present invention will vary somewhat from dyestuff to dyestuff. In some cases the difierence is so great that the color is actually different than that of a control dyeing in which the dyeing assistant is not employed. The invention, however, is applicable generally to all metalized dyes which contain an amino group ortho to the azo group. However, it is particularly useful with chromium dyes, although improved results are obtained with dyes metalized with copper, iron, manganese, cobalt and other metalizing metals.

It is an advantage of the present invention that there is no substantial change in the other features of the dyeing operation and the dyer, therefore, does not have to learn a new technique. Thus, for example, the temperature is not critical and may range from room temperature to 160 C. The temperature, of course, will vary somewhat with the fiber dyed, but the customary temperatures used without the dyeing assistants of the present invention are equally usable when the dyeing assistants are present and the advantages of the present invention are obtained. In addition to the brighter shades and unchanged colors which are the principal advantages of the process of the present invention, it is a further advantage of the inven- 3,003,843 Patented Oct. 10, 1961 tion that these improved results are not obtained at the cost of other disadvantages. In fact, the dyeing actually produces other advantages. Thus, for example in the case of wool, the most important fiber for use of the present invention, there is decreased tendering and the wool is somewhat less harsh, the degree of improvement of course depending on the other factors of the dyeing procedure, such as temperature, time and so forth.

Another advantage of the present invention is that it imparts a degree of wrinkle resistance to the dyed fabric under conditions of high relative humidity. It also imparts better press retention when suflicient of the material is used. This property, as such, is not claimed in the present application. However, to the extent that wrinkle resistance is imparted, the present process produces a fabric having certain desirable properties as well as a better dyeing. The present invention is not, however, limited to dyeing procedures in which there will be substantial wrinkle resistance in addition to the improvement in dyeing. Thus, for example, the process may be used with so little dyeing assistant that no substantial increase in wrinkle resistance results.

The amounts of the esters of oxymethylene glycols used in the process of the present invention are not critical.

Noticeable improvement in dyeing results with as little as V 0.5% of the assistant, based on the weight of the fiber treated. Better results are obtained with larger amounts, such as l.53%. Still larger amounts may be used in many cases, as 10% or more usually does no harm. These larger amounts may also be desirable where the dyed fabric may be exposed to conditions of high relative humidity and greater wrinkle resistance is needed, as the wrinkle resistance in general requires larger amounts of the assistants than are needed to produce brighter and stronger dyeings.

The present invention is not limited to processes in which all of the assistant is added or present at the start of the dyeing. On the contrary, it is perfectly possible to add the assistant to the dye bath during the dyeing before completion and, particularly where larger amounts of the dyeing assistant is used, the addition may be in stages throughout the dyeing procedure. Thus, for example, in a dyeing process lasting six hours, the dyeing may be started cold without any assistant. Additions of 25-33% of the total assistant to be used may be made when the dye bath reaches the boil and each two hours thereafter. If, in fact, the prevention of demetalization is the only or major reason for the improved results of the present invention, it would appear that the assistants may effect some remetalization. Otherwise, it is diflicult to explain the results which are obtained when the dyeing is started without any assistant and the assistant only added after the dyeing is partially complete. Of course, other factors may be involved and, as pointed out above, the present invention is not intended to be limited to any theoretical mechanism.

It is possible to obtain at least part of the advantages of the present invention by treating the nitrogenous fabric with the diester of oxymethylene glycols and then dyeing. However, the improvement is not quite as marked with the same amount of assistant and, therefore, while the multi-step operation described above is included within the broad scope of the present invention, the preferred embodiment is to have the assistant present in the dye bath itself. 1

The diesters of oxymethylene glycols are for the most part known compounds, although one, the diformate of dimethylene glycol, is in fact a new compound. This compound is not claimed in the present invention as it forms a part of the subject matter of the copending application of A. F. DAdamo, Jr., Serial No. 629,226, filed December 19, 1956, now abandoned. A number of typical diesters of oxymethylene glycol are the diesters of lower fatty acids, such as formic, acetic, propionic, and the like, of methylene glycol polymers, such as oxydimethylene glycol, dioxytrimethylene glycol, trioxytetramethylene glycol, tetraoxypentamethylene glycol, pentaoxyhexamethylene glycol and the like. Where in the formula in is greater than 1, the esters are of glycols which, in addition to the terminal oxymethylene groups, have one or more oxyethylene or oxypropylene groups.

While wool is the most important fiber for the process of the present invention, it is not limited thereto as the same problems are encountered with other protein fibers, such as silk, casein fibers such as the one sold under the name Aralac, mohair and the like. In general the fiber dyed appears to effect but little the factor of improved brightness and strength of dyeing, although the other properties, such as less tendering, wrinkle resistance and the like will, of course, vary with different fibers.

The invention will be described in greater detail in conjunction with the following specific examples in which the parts are by weight unless otherwise specified.

Exam pla 1 The azo dyestutf of the above formula, metalized with one atom of chromium per mol of dyestuff, was used in dyeing wool in a dye bath at 2% strength in 8% sulfuric acid, both percentages being based on the weight of the wool. 2% of dimethylene glycol diacetate, also based on the weight of the wool, was added to the dye bath which was brought to a boil and boiled until dyeing was complete and uniform.

The wool dyed a beautiful bright yellow-green, whereas when the dyeing was effected under identical conditions without the dimethylene glycol diacetate, the green had no yellowish shade but was blue and dull.

Example 2 The procedure of Example 1 was followed but the dimethylene glycol diacetate was not added until the bath had reached the boil. The result was identical with that of Example 1 where the dimethylene glycol diacetate was present from the beginning.

Example 3 The procedure of Example 1 was repeated but using 8% of an emulsion containing 25% of dimethylene glycol diacetate, 25% xylene, emulsifying agent which is ethylene oxide condensed with a base formed by the condensation of propylene oxide with propylene glycol, and 45% water. The results are the same as in Example 1. It is to be noted that the effect of the dimethylene glycol diacetate is not influenced by the method of dispersion in the dye bath.

Example 4 Dimethylene glycol diformate was prepared as follows. To a suspension of 68.0 g. sodium formate (1.0 mol) in 200 ml. of dry dimethylformamide, 57.5 g. of his chloromethyl ether (0.5 mol) was added dropwise over one hour with vigorous stirring at 90 C. The mixture was cooled to room temperature and allowed to stand for four hours.

The precipitated sodium chloride was filtered and washed with dimethylformarnide. The combined filtrate was then vacuum distilled and a fraction weighing 28 grams and boiling at 70 C. at 1 mm. mercury pressure was collected,

The dimethylene glycol diformate was then used in the procedure of Example 3. The resulting dyeing had the same desirable bright yellowish green shade.

Example 5 The procedure of Example 1 was repeated but 8% of dimethylene glycol diacetate was used. The color of the dyed wool was the same but a greater degree of wrinkle resistance at high relative humidities was ob 10 tained.

Example 6 The procedure of Example 3 was repeated replacing the wool with a corresponding amount of casein fiber sold under the name of Aralac. The dyeing was just as bright as in the case of wool and, when the procedure was repeated omitting the dimethylene glycol diacetate, a much bluer and duller dyeing resulted.

Example 7 Example 3 was repeated using 2.5% of the diacetate of a polyoxymethylene glycol mixture with an average corresponding to tetrarnethylene glycol. The results were the same as in Example 3.

Example 8 The procedure of Example 1 was repeated but using 2.5% of the compound having the formula H H CHzU-O-GH2"OCH2CH2'OCH2OCCH3 The same bright yellowish green dyeing was obtained.

Example 9 (HI HrN SOsH The procedure of Example 1 was repeated using the dyestuif of the above formula fully metalized with one atom of chromium. A bright, clean yellow-green shade was obtained.

Example 10 OH HzN O.N N N 8 The procedure of Example 1 was repeated, using the above dyestuff metalized with one atom of chromium.

Again the shade was a bright yellow-green, whereas under the same conditions without dimethylene glycol diacetate a blue, dull shade was obtained.

The procedure of Example 1 was followed, using the dyestuif of the above formula metalized with one atom of chromium. A bright yellow shade of green was obtained, whereas under the same conditions without dimethylene glycol diacetate the shade was blue and dull.

Example 12 SOaH The procedure of Example 1 was followed using the dyestufi of the above formula metalized with one atom of chromium. When dyed in the presence of dimethylene glycol diacetate a bright slate green was obtained, whereas when dirnethylene glycol diacetate was absent the shade was a dull gray-green.

Example 13 N02 SOsH The procedure of the preceding example was followed using the chromium complex of the dyes-tufif of the above formula, the results being substantially the same as those of the preceding example.

Example 14 HO 3S The procedure of Example 3 was followed substituting the chromium complex of the dyestuff of the above formula. The results were similar to those of Example 3.

Example HQN I IO2 I SIOSH The procedure of Example 14 is repeated substituting the chromium complex of the dyestuff of the above formula. A gray-green shade was obtained, whereas if the dimethylene glycol diacetate is omitted a reddish The procedure of Example 1 was followed, substituting the chromium complex of the dyestuff of the above formula. In the presence of dimethylene glycol diacetate a brighter and yellower green shade was obtained than when the dyeing was carried out in sulfuric acid only and which caused a blue-green shade to be obtained.

Example 1 7 (3H fllzN The procedure of Example 3 was followed substituting the chromium complex of the dyestulf of the above formula. A rich taupe shade is obtained, whereas when the emulsion of dimethylene glycol diacetate is omitted a reddish tan shade is obtained.

Example 18 OH NHa The azo dyestufi of the above formula metalized with one atom of chromium per mol of dyestuff, was used in dyeing wool in a dye bath at 2% strength in 8% sulfuric acid, both percentages being based on the weight of the wool. 2% of dimethylene glycol diacetate, also based on the weight of the wool, was added to the dye bath which was brought to a boil and boiled until dyeing was complete and uniform.

The wool dyed a beautiful bright yellow-green, whereas When the dyeing was effected under identical conditions without the dimethylene glycol diacetate, the green had no yellowish shade but was blue and dull.

I claim:

1. A method of dyeing basic nitrogenous fibers with metalized acid azo dyes containing an amino group and a hydroxy group, both groups being ortho to an azo group which comprises effecting dyeing in the presence of an effective amount of a diester of an oxymethylene glycol having the formula where R is selected from the group consisting of hydrogen, alkyl and an aryl radical and m is an integer selected from one, two and three and n is an integer selected from zero, one, two, three and four.

2. A method of dyeing basic nitrogenous fibers with metalized acid monazo dyes containing an amino grou and a hydroxy group, both groups being ortho to an azo group which comprises efiecting dyeing in the presence of an effective amount of a diester of an oxymethylene glycol having the formula 0 0 R( J-O CHz(O[OH2lm) nO OH:O(I.I'ER Where R is selected from the group consisting of hydrogen, alkyl and an aryl radical and m is an integer selected from one, two and three and n is an integer selected from zero, one, two, three and four.

3. A method according to claim 1 in which the ester is a di(lower fatty acid)ester.

4. A method according to claim 3 in which the glycol is a polymethylene glycol.

5. A method according to claim 2 in which the ester is a di(lower fatty acid)ester.

6. A method according to claim 5 in which the glycol is a polymethylene glycol.

7. A method according to claim 2 in which the ester is dimethylene glycol diacetate.

8. A dyestufl composition comprising a metalized azo dyestuif having an amino group and a hydroxy group, both groups being ortho to an azo group and an effective amount of a diester of an oxymethylene glycol having the formula R*( i00H2-(0[o1n]m)n0oHl0ii-R where R is selected from the group consisting of hydrogen, alkyl and an aryl radical and m is an integer selected from one, two and three and n is an integer selected from Zero, one, two, three and four.

9. A dyestuif composition comprising a metalized monazo dyestuif having an amino group and a hydroxy group,

both groups being ortho to an azo group and an effective amount of a diester of an oxymethylene glycol having the formula where R is selected from the group consisting of hydrogen, alkyl and an aryl radical and m is an integer selected from one, two and three and n is an integer selected from zero, one, two, three and four.

10. A composition according to claim 9 in which the ester is a lower fatty acid ester of a polyrnethylene glycol.

11. A method according to claim 10 in which the ester is dirncthylene glycol diacetate.

References Cited in the file of this patent UNITED STATES PATENTS 2,422,586 Royer June 17, 1947 8 Cook Oct. 3, 1950 Games Aug. 18, 1953 Davis Sept. 17, 1957 Laucius May 20, 1958 OTHER REFERENCES 

1. A METHOD OF DYEING BASIC NITROGENOUS FIBERS WITH METALIZED ACID AZO DYES CONTAINING AN AMINO GROUP AND A HYDROXY GROUP, BOTH GROUPS BEING ORTHO TO AN AZO GROUP WHICH COMPRISES EFFECTING DYEING IN THE PRESENCE OF AN EFFECTIVE AMOUNT OF A DIESTER OF AN OXYMETHYLENE GLYCOL HAVING THE FORMULA 